/*
 * Copyright (c) 2000, 2013, Oracle and/or its affiliates. All rights reserved.
 * ORACLE PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
 *
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/*
 * @author    IBM Corp.
 *
 * Copyright IBM Corp. 1999-2000.  All rights reserved.
 */

package javax.management.modelmbean;

import static com.sun.jmx.defaults.JmxProperties.MODELMBEAN_LOGGER;

import com.sun.jmx.mbeanserver.GetPropertyAction;

import java.io.IOException;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.io.ObjectStreamField;
import java.lang.reflect.Method;
import java.security.AccessController;
import java.util.logging.Level;

import javax.management.Descriptor;
import javax.management.DescriptorKey;
import javax.management.DescriptorAccess;
import javax.management.MBeanAttributeInfo;
import javax.management.RuntimeOperationsException;

/**
 * <p>The ModelMBeanAttributeInfo object describes an attribute of the ModelMBean.
 * It is a subclass of MBeanAttributeInfo with the addition of an associated Descriptor
 * and an implementation of the DescriptorAccess interface.</p>
 *
 * <P id="descriptor">
 * The fields in the descriptor are defined, but not limited to, the following.
 * Note that when the Type in this table is Number, a String that is the decimal
 * representation of a Long can also be used.</P>
 *
 * <table border="1" cellpadding="5" summary="ModelMBeanAttributeInfo Fields">
 * <tr><th>Name</th><th>Type</th><th>Meaning</th></tr>
 * <tr><td>name</td><td>String</td>
 * <td>Attribute name.</td></tr>
 * <tr><td>descriptorType</td><td>String</td>
 * <td>Must be "attribute".</td></tr>
 * <tr id="value-field"><td>value</td><td>Object</td>
 * <td>Current (cached) value for attribute.</td></tr>
 * <tr><td>default</td><td>Object</td>
 * <td>Default value for attribute.</td></tr>
 * <tr><td>displayName</td><td>String</td>
 * <td>Name of attribute to be used in displays.</td></tr>
 * <tr><td>getMethod</td><td>String</td>
 * <td>Name of operation descriptor for get method.</td></tr>
 * <tr><td>setMethod</td><td>String</td>
 * <td>Name of operation descriptor for set method.</td></tr>
 * <tr><td>protocolMap</td><td>Descriptor</td>
 * <td>See the section "Protocol Map Support" in the JMX specification
 * document.  Mappings must be appropriate for the attribute and entries
 * can be updated or augmented at runtime.</td></tr>
 * <tr><td>persistPolicy</td><td>String</td>
 * <td>One of: OnUpdate|OnTimer|NoMoreOftenThan|OnUnregister|Always|Never.
 * See the section "MBean Descriptor Fields" in the JMX specification
 * document.</td></tr>
 * <tr><td>persistPeriod</td><td>Number</td>
 * <td>Frequency of persist cycle in seconds. Used when persistPolicy is
 * "OnTimer" or "NoMoreOftenThan".</td></tr>
 * <tr><td>currencyTimeLimit</td><td>Number</td>
 * <td>How long <a href="#value=field">value</a> is valid: &lt;0 never,
 * =0 always, &gt;0 seconds.</td></tr>
 * <tr><td>lastUpdatedTimeStamp</td><td>Number</td>
 * <td>When <a href="#value-field">value</a> was set.</td></tr>
 * <tr><td>visibility</td><td>Number</td>
 * <td>1-4 where 1: always visible, 4: rarely visible.</td></tr>
 * <tr><td>presentationString</td><td>String</td>
 * <td>XML formatted string to allow presentation of data.</td></tr>
 * </table>
 *
 * <p>The default descriptor contains the name, descriptorType and displayName
 * fields.  The default value of the name and displayName fields is the name of
 * the attribute.</p>
 *
 * <p><b>Note:</b> because of inconsistencies in previous versions of
 * this specification, it is recommended not to use negative or zero
 * values for <code>currencyTimeLimit</code>.  To indicate that a
 * cached value is never valid, omit the
 * <code>currencyTimeLimit</code> field.  To indicate that it is
 * always valid, use a very large number for this field.</p>
 *
 * <p>The <b>serialVersionUID</b> of this class is <code>6181543027787327345L</code>.
 *
 * @since 1.5
 */

@SuppressWarnings("serial")  // serialVersionUID is not constant
public class ModelMBeanAttributeInfo
    extends MBeanAttributeInfo
    implements DescriptorAccess {

  // Serialization compatibility stuff:
  // Two serial forms are supported in this class. The selected form depends
  // on system property "jmx.serial.form":
  //  - "1.0" for JMX 1.0
  //  - any other value for JMX 1.1 and higher
  //
  // Serial version for old serial form
  private static final long oldSerialVersionUID = 7098036920755973145L;
  //
  // Serial version for new serial form
  private static final long newSerialVersionUID = 6181543027787327345L;
  //
  // Serializable fields in old serial form
  private static final ObjectStreamField[] oldSerialPersistentFields =
      {
          new ObjectStreamField("attrDescriptor", Descriptor.class),
          new ObjectStreamField("currClass", String.class)
      };
  //
  // Serializable fields in new serial form
  private static final ObjectStreamField[] newSerialPersistentFields =
      {
          new ObjectStreamField("attrDescriptor", Descriptor.class)
      };
  //
  // Actual serial version and serial form
  private static final long serialVersionUID;
  /**
   * @serialField attrDescriptor Descriptor The {@link Descriptor} containing the metadata
   * corresponding to this attribute
   */
  private static final ObjectStreamField[] serialPersistentFields;
  private static boolean compat = false;

  static {
    try {
      GetPropertyAction act = new GetPropertyAction("jmx.serial.form");
      String form = AccessController.doPrivileged(act);
      compat = (form != null && form.equals("1.0"));
    } catch (Exception e) {
      // OK: No compat with 1.0
    }
    if (compat) {
      serialPersistentFields = oldSerialPersistentFields;
      serialVersionUID = oldSerialVersionUID;
    } else {
      serialPersistentFields = newSerialPersistentFields;
      serialVersionUID = newSerialVersionUID;
    }
  }
  //
  // END Serialization compatibility stuff

  /**
   * @serial The {@link Descriptor} containing the metadata corresponding to this attribute
   */
  private Descriptor attrDescriptor = validDescriptor(null);

  private final static String currClass = "ModelMBeanAttributeInfo";

  /**
   * Constructs a ModelMBeanAttributeInfo object with a default
   * descriptor. The {@link Descriptor} of the constructed
   * object will include fields contributed by any annotations
   * on the {@code Method} objects that contain the {@link
   * DescriptorKey} meta-annotation.
   *
   * @param name The name of the attribute.
   * @param description A human readable description of the attribute. Optional.
   * @param getter The method used for reading the attribute value. May be null if the property is
   * write-only.
   * @param setter The method used for writing the attribute value. May be null if the attribute is
   * read-only.
   * @throws javax.management.IntrospectionException There is a consistency problem in the
   * definition of this attribute.
   */

  public ModelMBeanAttributeInfo(String name,
      String description,
      Method getter,
      Method setter)
      throws javax.management.IntrospectionException {
    super(name, description, getter, setter);

    if (MODELMBEAN_LOGGER.isLoggable(Level.FINER)) {
      MODELMBEAN_LOGGER.logp(Level.FINER,
          ModelMBeanAttributeInfo.class.getName(),
          "ModelMBeanAttributeInfo(" +
              "String,String,Method,Method)",
          "Entry", name);
    }

    attrDescriptor = validDescriptor(null);
    // put getter and setter methods in operations list
    // create default descriptor

  }

  /**
   * Constructs a ModelMBeanAttributeInfo object.  The {@link
   * Descriptor} of the constructed object will include fields
   * contributed by any annotations on the {@code Method}
   * objects that contain the {@link DescriptorKey}
   * meta-annotation.
   *
   * @param name The name of the attribute.
   * @param description A human readable description of the attribute. Optional.
   * @param getter The method used for reading the attribute value. May be null if the property is
   * write-only.
   * @param setter The method used for writing the attribute value. May be null if the attribute is
   * read-only.
   * @param descriptor An instance of Descriptor containing the appropriate metadata for this
   * instance of the Attribute. If it is null, then a default descriptor will be created.  If the
   * descriptor does not contain the field "displayName" this field is added in the descriptor with
   * its default value.
   * @throws javax.management.IntrospectionException There is a consistency problem in the
   * definition of this attribute.
   * @throws RuntimeOperationsException Wraps an IllegalArgumentException. The descriptor is
   * invalid, or descriptor field "name" is not equal to name parameter, or descriptor field
   * "descriptorType" is not equal to "attribute".
   */

  public ModelMBeanAttributeInfo(String name,
      String description,
      Method getter,
      Method setter,
      Descriptor descriptor)
      throws javax.management.IntrospectionException {

    super(name, description, getter, setter);
    // put getter and setter methods in operations list
    if (MODELMBEAN_LOGGER.isLoggable(Level.FINER)) {
      MODELMBEAN_LOGGER.logp(Level.FINER,
          ModelMBeanAttributeInfo.class.getName(),
          "ModelMBeanAttributeInfo(" +
              "String,String,Method,Method,Descriptor)",
          "Entry", name);
    }
    attrDescriptor = validDescriptor(descriptor);
  }

  /**
   * Constructs a ModelMBeanAttributeInfo object with a default descriptor.
   *
   * @param name The name of the attribute
   * @param type The type or class name of the attribute
   * @param description A human readable description of the attribute.
   * @param isReadable True if the attribute has a getter method, false otherwise.
   * @param isWritable True if the attribute has a setter method, false otherwise.
   * @param isIs True if the attribute has an "is" getter, false otherwise.
   */
  public ModelMBeanAttributeInfo(String name,
      String type,
      String description,
      boolean isReadable,
      boolean isWritable,
      boolean isIs) {

    super(name, type, description, isReadable, isWritable, isIs);
    // create default descriptor
    if (MODELMBEAN_LOGGER.isLoggable(Level.FINER)) {
      MODELMBEAN_LOGGER.logp(Level.FINER,
          ModelMBeanAttributeInfo.class.getName(),
          "ModelMBeanAttributeInfo(" +
              "String,String,String,boolean,boolean,boolean)",
          "Entry", name);
    }
    attrDescriptor = validDescriptor(null);
  }

  /**
   * Constructs a ModelMBeanAttributeInfo object.
   *
   * @param name The name of the attribute
   * @param type The type or class name of the attribute
   * @param description A human readable description of the attribute.
   * @param isReadable True if the attribute has a getter method, false otherwise.
   * @param isWritable True if the attribute has a setter method, false otherwise.
   * @param isIs True if the attribute has an "is" getter, false otherwise.
   * @param descriptor An instance of Descriptor containing the appropriate metadata for this
   * instance of the Attribute. If it is null then a default descriptor will be created.  If the
   * descriptor does not contain the field "displayName" this field is added in the descriptor with
   * its default value.
   * @throws RuntimeOperationsException Wraps an IllegalArgumentException. The descriptor is
   * invalid, or descriptor field "name" is not equal to name parameter, or descriptor field
   * "descriptorType" is not equal to "attribute".
   */
  public ModelMBeanAttributeInfo(String name,
      String type,
      String description,
      boolean isReadable,
      boolean isWritable,
      boolean isIs,
      Descriptor descriptor) {
    super(name, type, description, isReadable, isWritable, isIs);
    if (MODELMBEAN_LOGGER.isLoggable(Level.FINER)) {
      MODELMBEAN_LOGGER.logp(Level.FINER,
          ModelMBeanAttributeInfo.class.getName(),
          "ModelMBeanAttributeInfo(String,String,String," +
              "boolean,boolean,boolean,Descriptor)",
          "Entry", name);
    }
    attrDescriptor = validDescriptor(descriptor);
  }

  /**
   * Constructs a new ModelMBeanAttributeInfo object from this
   * ModelMBeanAttributeInfo Object.  A default descriptor will
   * be created.
   *
   * @param inInfo the ModelMBeanAttributeInfo to be duplicated
   */

  public ModelMBeanAttributeInfo(ModelMBeanAttributeInfo inInfo) {
    super(inInfo.getName(),
        inInfo.getType(),
        inInfo.getDescription(),
        inInfo.isReadable(),
        inInfo.isWritable(),
        inInfo.isIs());
    if (MODELMBEAN_LOGGER.isLoggable(Level.FINER)) {
      MODELMBEAN_LOGGER.logp(Level.FINER,
          ModelMBeanAttributeInfo.class.getName(),
          "ModelMBeanAttributeInfo(ModelMBeanAttributeInfo)",
          "Entry");
    }
    Descriptor newDesc = inInfo.getDescriptor();
    attrDescriptor = validDescriptor(newDesc);
  }

  /**
   * Gets a copy of the associated Descriptor for the
   * ModelMBeanAttributeInfo.
   *
   * @return Descriptor associated with the ModelMBeanAttributeInfo object.
   * @see #setDescriptor
   */

  public Descriptor getDescriptor() {
    if (MODELMBEAN_LOGGER.isLoggable(Level.FINER)) {
      MODELMBEAN_LOGGER.logp(Level.FINER,
          ModelMBeanAttributeInfo.class.getName(),
          "getDescriptor()", "Entry");
    }
    if (attrDescriptor == null) {
      attrDescriptor = validDescriptor(null);
    }
    return ((Descriptor) attrDescriptor.clone());
  }


  /**
   * Sets associated Descriptor (full replace) for the
   * ModelMBeanAttributeDescriptor.  If the new Descriptor is
   * null, then the associated Descriptor reverts to a default
   * descriptor.  The Descriptor is validated before it is
   * assigned.  If the new Descriptor is invalid, then a
   * RuntimeOperationsException wrapping an
   * IllegalArgumentException is thrown.
   *
   * @param inDescriptor replaces the Descriptor associated with the ModelMBeanAttributeInfo
   * @throws RuntimeOperationsException Wraps an IllegalArgumentException for an invalid Descriptor
   * @see #getDescriptor
   */
  public void setDescriptor(Descriptor inDescriptor) {
    attrDescriptor = validDescriptor(inDescriptor);
  }

  /**
   * Creates and returns a new ModelMBeanAttributeInfo which is a duplicate of this
   * ModelMBeanAttributeInfo.
   *
   * @throws RuntimeOperationsException for illegal value for field Names or field Values.  If the
   * descriptor construction fails for any reason, this exception will be thrown.
   */

  @Override
  public Object clone() {
    if (MODELMBEAN_LOGGER.isLoggable(Level.FINER)) {
      MODELMBEAN_LOGGER.logp(Level.FINER,
          ModelMBeanAttributeInfo.class.getName(),
          "clone()", "Entry");
    }
    return (new ModelMBeanAttributeInfo(this));
  }

  /**
   * Returns a human-readable version of the
   * ModelMBeanAttributeInfo instance.
   */
  @Override
  public String toString() {
    return
        "ModelMBeanAttributeInfo: " + this.getName() +
            " ; Description: " + this.getDescription() +
            " ; Types: " + this.getType() +
            " ; isReadable: " + this.isReadable() +
            " ; isWritable: " + this.isWritable() +
            " ; Descriptor: " + this.getDescriptor();
  }


  /**
   * Clones the passed in Descriptor, sets default values, and checks for validity.
   * If the Descriptor is invalid (for instance by having the wrong "name"),
   * this indicates programming error and a RuntimeOperationsException will be thrown.
   *
   * The following fields will be defaulted if they are not already set:
   * displayName=this.getName(),name=this.getName(),descriptorType = "attribute"
   *
   * @param in Descriptor to be checked, or null which is equivalent to an empty Descriptor.
   * @throws RuntimeOperationsException if Descriptor is invalid
   */
  private Descriptor validDescriptor(final Descriptor in) throws RuntimeOperationsException {

    Descriptor clone;
    boolean defaulted = (in == null);
    if (defaulted) {
      clone = new DescriptorSupport();
      MODELMBEAN_LOGGER.finer("Null Descriptor, creating new.");
    } else {
      clone = (Descriptor) in.clone();
    }

    //Setting defaults.
    if (defaulted && clone.getFieldValue("name") == null) {
      clone.setField("name", this.getName());
      MODELMBEAN_LOGGER.finer("Defaulting Descriptor name to " + this.getName());
    }
    if (defaulted && clone.getFieldValue("descriptorType") == null) {
      clone.setField("descriptorType", "attribute");
      MODELMBEAN_LOGGER.finer("Defaulting descriptorType to \"attribute\"");
    }
    if (clone.getFieldValue("displayName") == null) {
      clone.setField("displayName", this.getName());
      MODELMBEAN_LOGGER.finer("Defaulting Descriptor displayName to " + this.getName());
    }

    //Checking validity
    if (!clone.isValid()) {
      throw new RuntimeOperationsException(
          new IllegalArgumentException("Invalid Descriptor argument"),
          "The isValid() method of the Descriptor object itself returned false," +
              "one or more required fields are invalid. Descriptor:" + clone.toString());
    }
    if (!getName().equalsIgnoreCase((String) clone.getFieldValue("name"))) {
      throw new RuntimeOperationsException(
          new IllegalArgumentException("Invalid Descriptor argument"),
          "The Descriptor \"name\" field does not match the object described. " +
              " Expected: " + this.getName() + " , was: " + clone.getFieldValue("name"));
    }

    if (!"attribute".equalsIgnoreCase((String) clone.getFieldValue("descriptorType"))) {
      throw new RuntimeOperationsException(
          new IllegalArgumentException("Invalid Descriptor argument"),
          "The Descriptor \"descriptorType\" field does not match the object described. " +
              " Expected: \"attribute\" ," + " was: " + clone.getFieldValue("descriptorType"));
    }

    return clone;
  }


  /**
   * Deserializes a {@link ModelMBeanAttributeInfo} from an {@link ObjectInputStream}.
   */
  private void readObject(ObjectInputStream in)
      throws IOException, ClassNotFoundException {
    // New serial form ignores extra field "currClass"
    in.defaultReadObject();
  }


  /**
   * Serializes a {@link ModelMBeanAttributeInfo} to an {@link ObjectOutputStream}.
   */
  private void writeObject(ObjectOutputStream out)
      throws IOException {
    if (compat) {
      // Serializes this instance in the old serial form
      //
      ObjectOutputStream.PutField fields = out.putFields();
      fields.put("attrDescriptor", attrDescriptor);
      fields.put("currClass", currClass);
      out.writeFields();
    } else {
      // Serializes this instance in the new serial form
      //
      out.defaultWriteObject();
    }
  }

}
